Automatically resize Pong Walls to fit screen resolutions Help Needed.

Hey everyone,
I have this script (Not of my own making).

What it does:
It resizes the walls of my Pong level so that they fit the current screen resolution.

My Problem:
Originally it is supposed to resize the box colliders but I want it to resize the actual GameObject.
I tried to change the variables so that they are var topWall : GameObject ,etc but it gave me the error,

‘size’ is not a member of ‘UnityEngine.GameObject’ and
‘center’ is not a member of ‘UnityEngine.GameObject’

Original Code:

#pragma strict

//Reference the camera
var mainCam : Camera;

//Reference the colliders we are going to adjust
var topWall : BoxCollider2D;
var bottomWall : BoxCollider2D;
var leftWall : BoxCollider2D;
var rightWall : BoxCollider2D;

//Reference the players
var Player01 : Transform;
var Player02 : Transform;

function Start () { //Only set this to Update if you know the screen size can change during a playsession.

    //Move each wall to its edge location:
    topWall.size = new Vector2 (mainCam.ScreenToWorldPoint (new Vector3 (Screen.width * 2f, 0f, 0f)).x, 1f);
    topWall.center = new Vector2 (0f, mainCam.ScreenToWorldPoint (new Vector3 ( 0f, Screen.height, 0f)).y + 0.5f);
   
    bottomWall.size = new Vector2 (mainCam.ScreenToWorldPoint (new Vector3 (Screen.width * 2, 0f, 0f)).x, 1f);
    bottomWall.center = new Vector2 (0f, mainCam.ScreenToWorldPoint (new Vector3( 0f, 0f, 0f)).y - 0.5f);
   
    leftWall.size = new Vector2(1f, mainCam.ScreenToWorldPoint(new Vector3(0f, Screen.height*2f, 0f)).y);;
    leftWall.center = new Vector2(mainCam.ScreenToWorldPoint(new Vector3(0f, 0f, 0f)).x - 0.5f, 0f);
   
    rightWall.size = new Vector2(1f, mainCam.ScreenToWorldPoint(new Vector3(0f, Screen.height*2f, 0f)).y);
    rightWall.center = new Vector2(mainCam.ScreenToWorldPoint(new Vector3(Screen.width, 0f, 0f)).x + 0.5f, 0f);

    //Move the players to a fixed distance from the edges of the screen:
    Player01.position.x = mainCam.ScreenToWorldPoint (new Vector3 (75f, 0f, 0f)).x;
    Player02.position.x = mainCam.ScreenToWorldPoint (new Vector3 (Screen.width -75f, 0f, 0f)).x;
}

Have you tried the Transform?

Size: topWall.transform.localScale
Center (world): topWall.transform.position
Center (local): topWall.transform.localPosition

Hope that helps.